Research on the Technology of Integral Water Searching and Plugging for Two-Stage Casing Gas-Lift Wells in Sudan Oilfield

The combination structure of $9\,\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$8$}\right.\mbox{''}$ and $5\,\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\mbox{''}$ casing is used in some gas-lift wells in Sudan Oilfield. The existing mechanical water searching and plugging technology cannot meet the technical requirements of this type of well, so a integral water searching and plugging string for two-stage casing gas-lift well is developed. The string is composed of two kinds of packers and one kind of regulator. The two kinds of packers are set by hydraulic pressure synchronously to seal the layers of two kinds of casing. After the packers are set, the steel wire is used to fish and drop the blanking plug and search the water layer by layer to realize the adjustment of production layers. This process string has the characteristics of accurate water layer searching, reliable sealing, dynamic adjustment, etc. The string can realize water searching and plugging for two-stage casing wells by one trip. The string has been applied in well JS-2 in Sudan. After adjustment and plugging, the water cut is 25.6% lower than before. The effect of water control and oil production increase is significant, and the production life of the well is prolonged.